And depending on your set up, it may be easier to simply change the url and server path to phplugins (from you’re original post, you’re using phplugins I assume) in the Lightroom plugins, and then export and upload.
If you were using Publisher, then you would probably only need to export and upload Pages plus your gallery and autoindex templates. This way you wouldn’t need to edit index.php files or the contact, about, etc. files.
(you would need to change the API URL in the Publisher plugin)
But if you were using exported and uploaded galleries, you’ll have a lot of work ahead of you either editing all the gallery and autoindex index.php files manually or changing URLs and server paths in all your galleries and autoindexes and exporting and uploading them again.
If you were using phplugins to manage navigation, you would need to change the urls in your phplugins file.
As Daniel said, it might just be easier to get going in Backlight right away. If you have all your galleries organized in collections, it would be pretty easy to get everything back on line relatively quickly just using the default design settings. Then you could set about re-designing. And designing in Backlight is much, much, much easier than dealing with the Lightroom Web Module.